generic_rsync.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2024 Denis Corbin
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// to contact the author, see the AUTHOR file
/*********************************************************************/
 
 
 
#ifndef GENERIC_RSYNC_HPP
#define GENERIC_RSYNC_HPP
 
#include "../my_config.h"
 
extern "C"
{
#if HAVE_LIBRSYNC_H
#include <librsync.h>
#endif
}
 
#include "generic_file.hpp"
#include "erreurs.hpp"
 
namespace libdar
{
 
 
 
    class generic_rsync : public generic_file
    {
    public:
 
    generic_rsync(generic_file *signature_storage,
              U_I signature_block_size,
              generic_file *below);
 
 
    generic_rsync(generic_file *base_signature,
              generic_file *below,
              const infinint & crc_size,
              const crc **checksum);
 
 
    generic_rsync(generic_file *current_data,
              generic_file *delta);
 
 
    generic_rsync(const generic_rsync & ref) = delete;
    generic_rsync(generic_rsync && ref) noexcept = delete;
    generic_rsync & operator = (const generic_rsync & ref) = delete;
    generic_rsync & operator = (generic_rsync && ref) noexcept = delete;
 
    ~generic_rsync() noexcept(false);
 
        // inherited from generic_file
 
    virtual bool skippable(skippability direction, const infinint & amount) override { return false; };
    virtual bool skip(const infinint & pos) override {if(pos != 0 || !initial) throw SRC_BUG; else return true; };
    virtual bool skip_to_eof() override { throw SRC_BUG; };
    virtual bool skip_relative(S_I x) override { if(x != 0) throw SRC_BUG; else return true; };
    virtual bool truncatable(const infinint & pos) const override { return pos == get_position(); };
    virtual infinint get_position() const override { return x_below->get_position(); };
 
    protected:
    virtual void inherited_read_ahead(const infinint & amount) override {};
    virtual U_I inherited_read(char *a, U_I size) override;
    virtual void inherited_write(const char *a, U_I size) override;
    virtual void inherited_truncate(const infinint & pos) override { if(pos != get_position()) throw SRC_BUG; };
    virtual void inherited_sync_write() override {};
    virtual void inherited_flush_read() override {};
    virtual void inherited_terminate() override;
 
    private:
    enum { sign, delta, patch } status;
 
    generic_file *x_below;    
    generic_file *x_input;
    generic_file *x_output;
    bool initial;
    char *working_buffer;
    U_I working_size;
    bool patching_completed;
    crc *data_crc;
 
#if LIBRSYNC_AVAILABLE
    rs_job_t *job;
    rs_signature_t *sumset;
 
    static rs_result patch_callback(void *opaque,
                    rs_long_t pos,
                    size_t *len,
                    void **buf);
#endif
 
 
    bool step_forward(const char *buffer_in,
              U_I & avail_in,
              bool shift_input,
              char *buffer_out,
              U_I & avail_out);
    void free_job();
    void send_eof();
    };
 
 
} // end of namespace
 
#endif